/* -*- mode: C++ ; c-file-style: "stroustrup" -*- *****************************
 * Qwt Widget Library
 * Copyright (C) 1997   Josef Wilgen
 * Copyright (C) 2002   Uwe Rathmann
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the Qwt License, Version 1.0
 *****************************************************************************/

// vim: expandtab

#include <qwindowdefs.h>
#include <qwidget.h>
#include <qrect.h>
#include <qpainter.h>
#include <qpalette.h>
#include <qpaintdevice.h>
#include <qpixmap.h>
#include <qstyle.h>
#if QT_VERSION < 0x040000
#include <qsimplerichtext.h>
#else
#include <qtextdocument.h>
#include <qabstracttextdocumentlayout.h>
#include <qstyleoption.h>
#include <qpaintengine.h>
#endif

#include "qwt_math.h"
#include "qwt_clipper.h"
#include "qwt_color_map.h"
#include "qwt_scale_map.h"
#include "qwt_painter.h"

QwtMetricsMap QwtPainter::d_metricsMap;

#if defined(Q_WS_X11)
bool QwtPainter::d_deviceClipping = true;
#else
bool QwtPainter::d_deviceClipping = false;
#endif

#if QT_VERSION < 0x040000
bool QwtPainter::d_SVGMode = false;
#endif

static inline bool isClippingNeeded(const QPainter *painter, QRect &clipRect)
{
    bool doClipping = false;
#if QT_VERSION >= 0x040000
    const QPaintEngine *pe = painter->paintEngine();
    if ( pe && pe->type() == QPaintEngine::SVG )
#else
    if ( painter->device()->devType() == QInternal::Picture )
#endif
    {
        // The SVG paint engine ignores any clipping,

        if ( painter->hasClipping() )
        {
            doClipping = true;
            clipRect = painter->clipRegion().boundingRect();
        }
    }

    if ( QwtPainter::deviceClipping() )
    {
        if (painter->device()->devType() == QInternal::Widget ||
          painter->device()->devType() == QInternal::Pixmap )
        {
            if ( doClipping )
            {
                clipRect &= QwtPainter::deviceClipRect();
            }
            else
            {
                doClipping = true;
                clipRect = QwtPainter::deviceClipRect();
            }
        }
    }

    return doClipping;
}

/*!
  \brief En/Disable device clipping. 

  On X11 the default for device clipping is enabled, 
  otherwise it is disabled.
  \sa QwtPainter::deviceClipping()
*/
void QwtPainter::setDeviceClipping(bool enable)
{
    d_deviceClipping = enable;
}

/*!
  Returns rect for device clipping
  \sa QwtPainter::setDeviceClipping()
*/
const QRect &QwtPainter::deviceClipRect()
{
    static QRect clip;

    if ( !clip.isValid() )
    {
        clip.setCoords(QWT_COORD_MIN, QWT_COORD_MIN,
            QWT_COORD_MAX, QWT_COORD_MAX);
    }
    return clip;
}

#if QT_VERSION < 0x040000 

/*!
  \brief En/Disable SVG mode. 

  When saving a QPicture to a SVG some texts are misaligned.
  In SVGMode QwtPainter tries to fix them. 

  \sa QwtPainter::isSVGMode()
  \note A QPicture that is created in SVG mode and saved to the
        native format, will be misaligned. Also it is not possible to
        reload and play a SVG document, that was created in SVG mode.
*/
void QwtPainter::setSVGMode(bool on)
{
    d_SVGMode = on;
}

bool QwtPainter::isSVGMode()
{
    return d_SVGMode;
}

#endif // QT_VERSION < 0x040000

/*!
  Scale all QwtPainter drawing operations using the ratio
  QwtPaintMetrics(from).logicalDpiX() / QwtPaintMetrics(to).logicalDpiX()
  and QwtPaintMetrics(from).logicalDpiY() / QwtPaintMetrics(to).logicalDpiY()

  \sa QwtPainter::resetScaleMetrics(), QwtPainter::scaleMetricsX(),
        QwtPainter::scaleMetricsY()
*/
void QwtPainter::setMetricsMap(const QPaintDevice *layout,
    const QPaintDevice *device)
{
    d_metricsMap.setMetrics(layout, device);
}

/*! 
  Change the metrics map 
  \sa QwtPainter::resetMetricsMap(), QwtPainter::metricsMap()
*/
void QwtPainter::setMetricsMap(const QwtMetricsMap &map)
{
    d_metricsMap = map;
}

/*! 
   Reset the metrics map to the ratio 1:1
   \sa QwtPainter::setMetricsMap(), QwtPainter::resetMetricsMap()
*/
void QwtPainter::resetMetricsMap()
{
    d_metricsMap = QwtMetricsMap();
}

/*!
  \return Metrics map
*/
const QwtMetricsMap &QwtPainter::metricsMap()
{
    return d_metricsMap;
}

/*!
    Wrapper for QPainter::setClipRect()
*/
void QwtPainter::setClipRect(QPainter *painter, const QRect &rect)
{
    painter->setClipRect(d_metricsMap.layoutToDevice(rect, painter));
}

/*!
    Wrapper for QPainter::drawRect()
*/
void QwtPainter::drawRect(QPainter *painter, int x, int y, int w, int h) 
{
    drawRect(painter, QRect(x, y, w, h));
}

/*!
    Wrapper for QPainter::drawRect()
*/
void QwtPainter::drawRect(QPainter *painter, const QRect &rect) 
{
    const QRect r = d_metricsMap.layoutToDevice(rect, painter);

    QRect clipRect;
    const bool deviceClipping = isClippingNeeded(painter, clipRect);

    if ( deviceClipping )
    {
        if ( !clipRect.intersects(r) )
            return;

        if ( !clipRect.contains(r) )
        {
            fillRect(painter, r & clipRect, painter->brush());

            int pw = painter->pen().width();
            pw = pw % 2 + pw / 2;

            QwtPolygon pa(5);
            pa.setPoint(0, r.left(), r.top());
            pa.setPoint(1, r.right() - pw, r.top());
            pa.setPoint(2, r.right() - pw, r.bottom() - pw);
            pa.setPoint(3, r.left(), r.bottom() - pw);
            pa.setPoint(4, r.left(), r.top());

            painter->save();
            painter->setBrush(Qt::NoBrush);
            drawPolyline(painter, pa);
            painter->restore();

            return;
        }
    }

    painter->drawRect(r);
}

/*!
    Wrapper for QPainter::fillRect()
*/
void QwtPainter::fillRect(QPainter *painter, 
    const QRect &rect, const QBrush &brush)
{
    if ( !rect.isValid() )
        return;

    QRect clipRect;
    const bool deviceClipping = isClippingNeeded(painter, clipRect);

#if QT_VERSION >= 0x040000
    /*
      Performance of Qt4 is horrible for non trivial brushs. Without
      clipping expect minutes or hours for repainting large rects
      (might result from zooming)
    */

    if ( deviceClipping )
        clipRect &= painter->window();
    else
        clipRect = painter->window();

    if ( painter->hasClipping() )
        clipRect &= painter->clipRegion().boundingRect();
#endif

    QRect r = d_metricsMap.layoutToDevice(rect, painter);
    if ( deviceClipping )
        r = r.intersect(clipRect);

    if ( r.isValid() )
        painter->fillRect(r, brush);
}

/*!
    Wrapper for QPainter::drawPie()
*/
void QwtPainter::drawPie(QPainter *painter, const QRect &rect, 
    int a, int alen)
{
    const QRect r = d_metricsMap.layoutToDevice(rect, painter);

    QRect clipRect;
    const bool deviceClipping = isClippingNeeded(painter, clipRect);
    if ( deviceClipping && !clipRect.contains(r) )
        return;

    painter->drawPie(r, a, alen);
}

/*!
    Wrapper for QPainter::drawEllipse()
*/
void QwtPainter::drawEllipse(QPainter *painter, const QRect &rect)
{
    QRect r = d_metricsMap.layoutToDevice(rect, painter);

    QRect clipRect;
    const bool deviceClipping = isClippingNeeded(painter, clipRect);

    if ( deviceClipping && !clipRect.contains(r) )
        return;

#if QT_VERSION >= 0x040000
    if ( painter->pen().style() != Qt::NoPen &&
        painter->pen().color().isValid() )
    {
        // Qt4 adds the pen to the rect, Qt3 not.
        int pw = painter->pen().width();
        if ( pw == 0 )
            pw = 1;

        r.setWidth(r.width() - pw);
        r.setHeight(r.height() - pw);
    }
#endif

    painter->drawEllipse(r);
}

/*!
    Wrapper for QPainter::drawText()
*/
void QwtPainter::drawText(QPainter *painter, int x, int y, 
        const QString &text)
{
    drawText(painter, QPoint(x, y), text);
}

/*!
    Wrapper for QPainter::drawText()
*/
void QwtPainter::drawText(QPainter *painter, const QPoint &pos, 
        const QString &text)
{
    const QPoint p = d_metricsMap.layoutToDevice(pos, painter);

    QRect clipRect;
    const bool deviceClipping = isClippingNeeded(painter, clipRect);

    if ( deviceClipping && !clipRect.contains(p) )
        return;

    painter->drawText(p, text);
}

/*!
    Wrapper for QPainter::drawText()
*/
void QwtPainter::drawText(QPainter *painter, int x, int y, int w, int h, 
        int flags, const QString &text)
{
    drawText(painter, QRect(x, y, w, h), flags, text);
}

/*!
    Wrapper for QPainter::drawText()
*/
void QwtPainter::drawText(QPainter *painter, const QRect &rect, 
        int flags, const QString &text)
{
    QRect textRect = d_metricsMap.layoutToDevice(rect, painter);
#if QT_VERSION < 0x040000
    if ( d_SVGMode &&
        ( flags == 0 || flags & Qt::AlignVCenter ) 
        && painter->device()->devType() == QInternal::Picture )
    {
        /*
            Qt3 misalignes texts, when saving a text
            to a SVG image. 
         */
        textRect.setY(textRect.y() - painter->fontMetrics().height() / 4);
    }
#endif
    painter->drawText(textRect, flags, text);
}

#ifndef QT_NO_RICHTEXT

/*!
  Wrapper for QSimpleRichText::draw()
*/
#if QT_VERSION < 0x040000

void QwtPainter::drawSimpleRichText(QPainter *painter, const QRect &rect,
    int flags, QSimpleRichText &text)
{
    QColorGroup cg;
    cg.setColor(QColorGroup::Text, painter->pen().color());

    const QRect scaledRect = d_metricsMap.layoutToDevice(rect, painter);

    text.setWidth(painter, scaledRect.width());

    // QSimpleRichText is Qt::AlignTop by default

    int y = scaledRect.y();
    if (flags & Qt::AlignBottom)
        y += (scaledRect.height() - text.height());
    else if (flags & Qt::AlignVCenter)
        y += (scaledRect.height() - text.height())/2;

    text.draw(painter, scaledRect.x(), y, scaledRect, cg);
}
#else
void QwtPainter::drawSimpleRichText(QPainter *painter, const QRect &rect,
    int flags, QTextDocument &text)
{
    const QRect scaledRect = d_metricsMap.layoutToDevice(rect, painter);
    text.setPageSize(QSize(scaledRect.width(), QWIDGETSIZE_MAX));

    QAbstractTextDocumentLayout* layout = text.documentLayout();

    const int height = qRound(layout->documentSize().height());
    int y = scaledRect.y();
    if (flags & Qt::AlignBottom)
        y += (scaledRect.height() - height);
    else if (flags & Qt::AlignVCenter)
        y += (scaledRect.height() - height)/2;

    QAbstractTextDocumentLayout::PaintContext context;
    context.palette.setColor(QPalette::Text, painter->pen().color());

    painter->save();

    painter->translate(scaledRect.x(), y);
    layout->draw(painter, context);

    painter->restore();
}
#endif

#endif // !QT_NO_RICHTEXT


/*!
  Wrapper for QPainter::drawLine()
*/
void QwtPainter::drawLine(QPainter *painter, int x1, int y1, int x2, int y2)
{
    QRect clipRect;
    const bool deviceClipping = isClippingNeeded(painter, clipRect);

    if ( deviceClipping && 
        !(clipRect.contains(x1, y1) && clipRect.contains(x2, y2)) )
    {
        QwtPolygon pa(2);
        pa.setPoint(0, x1, y1);
        pa.setPoint(1, x2, y2);
        drawPolyline(painter, pa);
        return;
    }

    if ( d_metricsMap.isIdentity() )
    {
#if QT_VERSION >= 0x030200 && QT_VERSION < 0x040000
        if ( !painter->device()->isExtDev() )
#endif
        {
            painter->drawLine(x1, y1, x2, y2);
            return;
        }
    }

    const QPoint p1 = d_metricsMap.layoutToDevice(QPoint(x1, y1));
    const QPoint p2 = d_metricsMap.layoutToDevice(QPoint(x2, y2));

#if QT_VERSION >= 0x030200 && QT_VERSION < 0x040000
    if ( painter->device()->isExtDev() )
    {
        // Strange: the postscript driver of QPrinter adds an offset 
        // of 0.5 to the start/endpoint when using drawLine, but not
        // for lines painted with drawLineSegments.

        QwtPolygon pa(2);
        pa.setPoint(0, p1);
        pa.setPoint(1, p2);
        painter->drawLineSegments(pa);
    }
    else
        painter->drawLine(p1, p2);
#else
    painter->drawLine(p1, p2);
#endif
}

/*!
  Wrapper for QPainter::drawPolygon()
*/
void QwtPainter::drawPolygon(QPainter *painter, const QwtPolygon &pa)
{
    QRect clipRect;
    const bool deviceClipping = isClippingNeeded(painter, clipRect);

    QwtPolygon cpa = d_metricsMap.layoutToDevice(pa);
    if ( deviceClipping )
    {
#ifdef __GNUC__
//#warning clipping ignores painter transformations
#endif
        cpa = QwtClipper::clipPolygon(clipRect, cpa);
    }
    painter->drawPolygon(cpa);
}

/*!
    Wrapper for QPainter::drawPolyline()
*/
void QwtPainter::drawPolyline(QPainter *painter, const QwtPolygon &pa)
{
    QRect clipRect;
    const bool deviceClipping = isClippingNeeded(painter, clipRect);

    QwtPolygon cpa = d_metricsMap.layoutToDevice(pa);
    if ( deviceClipping )
        cpa = QwtClipper::clipPolygon(clipRect, cpa);

#if QT_VERSION >= 0x040000
    bool doSplit = false;

    const QPaintEngine *pe = painter->paintEngine();
    if ( pe && pe->type() == QPaintEngine::Raster )
    {
        /*
            The raster paint engine seems to use some algo with O(n*n).
            ( Qt 4.3 is better than Qt 4.2, but remains unacceptable)
            To work around this problem, we have to split the polygon into
            smaller pieces.
         */
        doSplit = true;
    }

    if ( doSplit )
    {
        const int numPoints = cpa.size();
        const QPoint *points = cpa.data();

        const int splitSize = 20;
        for ( int i = 0; i < numPoints; i += splitSize )
        {
            const int n = qwtMin(splitSize + 1, cpa.size() - i);
            painter->drawPolyline(points + i, n);
        }
    }
    else
#endif
        painter->drawPolyline(cpa);
}

/*!
    Wrapper for QPainter::drawPoint()
*/

void QwtPainter::drawPoint(QPainter *painter, int x, int y)
{
    QRect clipRect;
    const bool deviceClipping = isClippingNeeded(painter, clipRect);

    const QPoint pos = d_metricsMap.layoutToDevice(QPoint(x, y));

    if ( deviceClipping && !clipRect.contains(pos) )
        return;

    painter->drawPoint(pos);
}

void QwtPainter::drawColoredArc(QPainter *painter, const QRect &rect, 
    int peak, int arc, int interval, const QColor &c1, const QColor &c2)
{
    int h1, s1, v1;
    int h2, s2, v2;

#if QT_VERSION < 0x040000
    c1.hsv(&h1, &s1, &v1);
    c2.hsv(&h2, &s2, &v2);
#else
    c1.getHsv(&h1, &s1, &v1);
    c2.getHsv(&h2, &s2, &v2);
#endif
    
    arc /= 2;
    for ( int angle = -arc; angle < arc; angle += interval)
    {
        double ratio;
        if ( angle >= 0 )
            ratio = 1.0 - angle / double(arc);
        else
            ratio = 1.0 + angle / double(arc);
            

        QColor c;
        c.setHsv( h1 + qRound(ratio * (h2 - h1)),
            s1 + qRound(ratio * (s2 - s1)),
            v1 + qRound(ratio * (v2 - v1)) );

        painter->setPen(QPen(c, painter->pen().width()));
        painter->drawArc(rect, (peak + angle) * 16, interval * 16);
    }
}

void QwtPainter::drawFocusRect(QPainter *painter, QWidget *widget)
{
    drawFocusRect(painter, widget, widget->rect());
}

void QwtPainter::drawFocusRect(QPainter *painter, QWidget *widget,
    const QRect &rect)
{
#if QT_VERSION < 0x040000
        widget->style().drawPrimitive(QStyle::PE_FocusRect, painter,
            rect, widget->colorGroup());
#else
        QStyleOptionFocusRect opt;
        opt.init(widget);
        opt.rect = rect;
        opt.state |= QStyle::State_HasFocus;

        widget->style()->drawPrimitive(QStyle::PE_FrameFocusRect, 
            &opt, painter, widget);
#endif

}

//!  Draw a round frame
#if QT_VERSION < 0x040000
void QwtPainter::drawRoundFrame(QPainter *painter, const QRect &rect,
    int width, const QColorGroup &cg, bool sunken)
#else
void QwtPainter::drawRoundFrame(QPainter *painter, const QRect &rect,
    int width, const QPalette &palette, bool sunken)
#endif
{

#if QT_VERSION < 0x040000
    QColor c0 = cg.mid();
    QColor c1, c2;
    if ( sunken )
    {
        c1 = cg.dark();
        c2 = cg.light();
    }
    else
    {
        c1 = cg.light();
        c2 = cg.dark();
    }
#else
    QColor c0 = palette.color(QPalette::Mid);
    QColor c1, c2;
    if ( sunken )
    {
        c1 = palette.color(QPalette::Dark);
        c2 = palette.color(QPalette::Light);
    }
    else
    {
        c1 = palette.color(QPalette::Light);
        c2 = palette.color(QPalette::Dark);
    }
#endif

    painter->setPen(QPen(c0, width));
    painter->drawArc(rect, 0, 360 * 16); // full

    const int peak = 150;
    const int interval = 2;

    if ( c0 != c1 )
        drawColoredArc(painter, rect, peak, 160, interval, c0, c1);
    if ( c0 != c2 )
        drawColoredArc(painter, rect, peak + 180, 120, interval, c0, c2);
}

void QwtPainter::drawColorBar(QPainter *painter,
        const QwtColorMap &colorMap, const QwtDoubleInterval &interval,
        const QwtScaleMap &scaleMap, Qt::Orientation orientation,
        const QRect &rect)
{
#if QT_VERSION < 0x040000
    QValueVector<QRgb> colorTable;
#else
    QVector<QRgb> colorTable;
#endif
    if ( colorMap.format() == QwtColorMap::Indexed )
        colorTable = colorMap.colorTable(interval);

    QColor c;

    const QRect devRect = d_metricsMap.layoutToDevice(rect);

    /*
      We paint to a pixmap first to have something scalable for printing
      ( f.e. in a Pdf document )
     */
      
    QPixmap pixmap(devRect.size());
    QPainter pmPainter(&pixmap);
    pmPainter.translate(-devRect.x(), -devRect.y());

    if ( orientation == Qt::Horizontal )
    {
        QwtScaleMap sMap = scaleMap;
        sMap.setPaintInterval(devRect.left(), devRect.right());

        for ( int x = devRect.left(); x <= devRect.right(); x++ )
        {
            const double value = sMap.invTransform(x);

            if ( colorMap.format() == QwtColorMap::RGB )
                c.setRgb(colorMap.rgb(interval, value));
            else
                c = colorTable[colorMap.colorIndex(interval, value)];

            pmPainter.setPen(c);
            pmPainter.drawLine(x, devRect.top(), x, devRect.bottom());
        }
    }
    else // Vertical
    {
        QwtScaleMap sMap = scaleMap;
        sMap.setPaintInterval(devRect.bottom(), devRect.top());

        for ( int y = devRect.top(); y <= devRect.bottom(); y++ )
        {
            const double value = sMap.invTransform(y);

            if ( colorMap.format() == QwtColorMap::RGB )
                c.setRgb(colorMap.rgb(interval, value));
            else
                c = colorTable[colorMap.colorIndex(interval, value)];

            pmPainter.setPen(c);
            pmPainter.drawLine(devRect.left(), y, devRect.right(), y);
        }
    }
    pmPainter.end();
    painter->drawPixmap(devRect, pixmap);
}

/*!
  \brief Scale a pen according to the layout metrics
    
  The width of non cosmetic pens is scaled from screen to layout metrics, 
  so that they look similar on paint devices with different resolutions.

  \param pen Unscaled pen
  \return Scaled pen
*/

QPen QwtPainter::scaledPen(const QPen &pen)
{
#if QT_VERSION < 0x040300
    return pen;
#else
    QPen sPen = pen;

    if ( !pen.isCosmetic() )
    {
        int pw = pen.width();
        if ( pw == 0 )
            pw = 1;

        sPen.setWidth(QwtPainter::metricsMap().screenToLayoutX(pw));
        sPen.setCosmetic(true);
    }

    return sPen;
#endif
}

